ISTANBUL (Reuters) - Turkey has called for an emergency meeting of the Organisation of Islamic Cooperation (OIC), the government spokesman said on Monday, after Israeli forces killed of dozens of protesters in Gaza.

Smoke rises in front of Palestinians who protest against U.S. embassy move to Jerusalem and ahead of the 70th anniversary of Nakba, at the Israel-Gaza border, May 14, 2018. REUTERS/Amir Cohen

Ankara wants the meeting of the 57-member-state body to be held on Friday, spokesman Bekir Bozdag said.

On the bloodiest single day for Palestinians since the Gaza conflict in 2014, Israeli troops shot dead 55 Palestinian protesters on the Gaza border on Monday as the United States opened its embassy to Israel in Jerusalem.

Turkey has been one of the most vocal critics of the U.S. move and the violence in Gaza, with the government declaring three days of mourning for those killed.

President Tayyip Erdogan described the actions of the Israeli forces as a “genocide” and Israel as a “terrorist state”.

“No matter from what side, whether from the United States or Israel, I curse this humanitarian plight, this genocide,” he said.

Prime Minister Binali Yildirim said the United States was an accomplice in a crime against humanity.

“Unfortunately, the U.S. has arrogantly stood by the Israeli administration which kills civilians and has partnered in this crime against humanity,” he told reporters in Ankara.

“This provocation will only worsen the problems in the region and cause a deeper mark in the Israeli-Palestinian relationship, and will make peace in the region more difficult,” Yildirim added.

He said U.S. President Donald Trump was attempting to distract attention from domestic problems by moving the embassy, “trying to hide the fire inside by setting fires outside”.

Palestinian Health Ministry officials said 55 protesters were killed and more than 2,700 injured either by live gunfire, tear gas or other means.

In Istanbul around 2,000 people marched down the main Istiklal Street, carrying banners saying “Jerusalem belongs to Muslims” and “Murderer Israel, get out of Palestine”.

Erdogan promised to hold a rally in support of Palestinians in Istanbul on Friday following the OIC summit.

Earlier on Monday, Turkey’s Foreign Ministry said the U.S. decision to move its embassy to Jerusalem had encouraged Israeli forces to kill dozens of Palestinian protesters.

“We curse the massacre carried out by Israeli security forces, encouraged by this step, on the Palestinians participating in peaceful demonstrations,” its statement said.